Nilpotent
Newbie
Before discussing memory tweaks, I will discuss a little how to enter the recovery mode as I've seen several posts on xda suggesting weird ways to enter the recovery mode. I wanted to post pictures but my camera does not focus well on the screen and the pictures are blurred for some reason.
Usual disclaimer: you are responsible of what you do with your system and if you follow any of what is written here, it is your choice. The more you go at low level, the more risk to break your phone...
What is the recovery mode for ?
Basically, you have no more warranty, you have played too much with your phone and it is soft bricked (boot loop, etc). The recovery mode offers the possibility to do a factory reset which may help you (I did not do it but I think you loose most of the phone apps and your data). If your phone works and you enter this mode, be careful as you can erase everything...
How to enter (stock) recovery mode.
1) Press an hold volume up
2) Press and hold power (do not release volume up)
3) When you see the samsung logo release the power button (if you don't release power, the phone may reboot several time and may end up to boot as usual).
3 bis) It may be ok to release volume up after you see the samsung logo but I usually keep it pressed until I see the android with the white open box.
4) After T-mobile exhibit II logo, you will see an android with a white open box. This is recovery
4bis) if you do nothing else, your phone will reboot.
5) Press the menu button (left button at the bottom of the screen), the screen will get darker. If it does not go darker, you probably missed the button and have to press again. If you pressed twice, the screen will go dark then back to normal and the phone will probably reboot normally.
6) After the screen goes dark, do nothing for a few seconds, the recovery menu will appear with the following options
- reboot system now
- apply update from sdcard
- wipe data/factory reset
- install fota
The reboot option is selected by default. To go down on the menu use volume down. To go up use volume up. To action the selected option, press home button (second button from the left at the bottom of the screen). If you press the menu button, the menu will disappear but the phone does not seem to reboot normally. If you can press menu again the see the recovery menu.
That's it !
Note: phone on battery vs phone plugged. It seems easier to boot in any mode when the phone is on battery. When it is plugged, pushing power does not work all the time, you may have to try several time. The problem to be on battery is if you are low on battery, you make a factory reset and you get out of battery in the middle of the process, I think you may be in really really big trouble.
Memory tweaks:
v6 supercharger (http://forum.xda-developers.com/showthread.php?t=991276)
I simply downloaded the version RC4 here
V6_SuperCharger_for_Android-update9_RC4.sh.pdf (http://forum.xda-developers.com/showpost.php?p=18703418&postcount=5021)
and followed the tutorial here
http://forum.xda-developers.com/showthread.php?t=1126940
I recommend to read and follow the tutorial and read what the script says !
Just in case, I give a few more details that may be different from the tutorial and could be helpful:
I renamed V6_SuperCharger_for_Android_update9_RC4.sh.pdf into V6_SuperCharger_for_Android_update9_RC4.sh (that does not matter apparently) and put it into /mnt/sdcard (or /sdcard, it's the same place)
I downloaded busybox v1.18.2 (in /system/bin) through busybox installer
When the script told me if I wanted to create local.prop (or else I would have a small chance of boot loop), I said yes.
I've been choosing option 6 (since then, I've used 7 and nitro lag nullifier by launching the script again)
Then I browse with script manager to /data/99Supercharger.sh and set it to launch as root and on boot.
I launched again supercharger but not sure it's useful.
Disabling verify-bytecode
Thanks for GVC to have mentioned this memory tweak some time ago (http://androidforums.com/samsung-exhibit-2-4g/475101-phone-memory-storage.html)
The full description is here. What I have written is basically a copy/paste adapted to the specifics of our phone
http://forum.xda-developers.com/showthread.php?t=1263119
I've done it (few months ago, this comes from the notes I took at that time) but stock ROM is odexed so it's not really useful for me but I can confirm that I had no problem with any apps since I've done this. So either I totally messed up or most of the apps are working fine... This is supposed to give a speed boost for deodexed ROMs (a lot of custom ROMs are deodexed).
I advise caution when you modify build.prop I have no idea what happens if you make a mistake with the file but I would say it's very very bad.
1) Open Terminal Emulator on phone or adb shell from PC and type the following.
adb shell (this is not needed from the terminal)
su
setprop dalvik.vm.verify-bytecode false
setprop dalvik.vm.dexopt-flags v=n,o=v
rm /data/dalvik-cache/*
2) Add these to /system/build.prop
dalvik.vm.verify-bytecode = false
dalvik.vm.dexopt-flags=v=n,o=v
(Copy local.prop or build.prop to SD and edit them. Copy back afterwards. If lines starting with dalvik.vm.verify-bytecode or dalvik.vm.dexopt-flags exist already, please modify them as above. )
For me, the end of the build.prop looks like this
#dalvik.vm.dexopt-flags=m=y
net.bt.name=Android
dalvik.vm.stack-trace-file=/data/anr/traces.txt
dalvik.vm.verify-bytecode = false
dalvik.vm.dexopt-flags=v=n,o=v
Also type following in adb shell or terminal emulator.
adb shell (this is not needed from the terminal)
su
rm /data/dalvik-cache/*
reboot
Reversing the change/undo tweak (I DID NOT TRY, I assume you have to revert the build.prop file first).
adb shell (this is not needed from the terminal)
su
setprop dalvik.vm.verify-bytecode true
rm /data/dalvik-cache/*
reboot
Usual disclaimer: you are responsible of what you do with your system and if you follow any of what is written here, it is your choice. The more you go at low level, the more risk to break your phone...
What is the recovery mode for ?
Basically, you have no more warranty, you have played too much with your phone and it is soft bricked (boot loop, etc). The recovery mode offers the possibility to do a factory reset which may help you (I did not do it but I think you loose most of the phone apps and your data). If your phone works and you enter this mode, be careful as you can erase everything...
How to enter (stock) recovery mode.
1) Press an hold volume up
2) Press and hold power (do not release volume up)
3) When you see the samsung logo release the power button (if you don't release power, the phone may reboot several time and may end up to boot as usual).
3 bis) It may be ok to release volume up after you see the samsung logo but I usually keep it pressed until I see the android with the white open box.
4) After T-mobile exhibit II logo, you will see an android with a white open box. This is recovery
4bis) if you do nothing else, your phone will reboot.
5) Press the menu button (left button at the bottom of the screen), the screen will get darker. If it does not go darker, you probably missed the button and have to press again. If you pressed twice, the screen will go dark then back to normal and the phone will probably reboot normally.
6) After the screen goes dark, do nothing for a few seconds, the recovery menu will appear with the following options
- reboot system now
- apply update from sdcard
- wipe data/factory reset
- install fota
The reboot option is selected by default. To go down on the menu use volume down. To go up use volume up. To action the selected option, press home button (second button from the left at the bottom of the screen). If you press the menu button, the menu will disappear but the phone does not seem to reboot normally. If you can press menu again the see the recovery menu.
That's it !
Note: phone on battery vs phone plugged. It seems easier to boot in any mode when the phone is on battery. When it is plugged, pushing power does not work all the time, you may have to try several time. The problem to be on battery is if you are low on battery, you make a factory reset and you get out of battery in the middle of the process, I think you may be in really really big trouble.
Memory tweaks:
v6 supercharger (http://forum.xda-developers.com/showthread.php?t=991276)
I simply downloaded the version RC4 here
and followed the tutorial here
http://forum.xda-developers.com/showthread.php?t=1126940
I recommend to read and follow the tutorial and read what the script says !
Just in case, I give a few more details that may be different from the tutorial and could be helpful:
I renamed V6_SuperCharger_for_Android_update9_RC4.sh.pdf into V6_SuperCharger_for_Android_update9_RC4.sh (that does not matter apparently) and put it into /mnt/sdcard (or /sdcard, it's the same place)
I downloaded busybox v1.18.2 (in /system/bin) through busybox installer
When the script told me if I wanted to create local.prop (or else I would have a small chance of boot loop), I said yes.
I've been choosing option 6 (since then, I've used 7 and nitro lag nullifier by launching the script again)
Then I browse with script manager to /data/99Supercharger.sh and set it to launch as root and on boot.
I launched again supercharger but not sure it's useful.
Disabling verify-bytecode
Thanks for GVC to have mentioned this memory tweak some time ago (http://androidforums.com/samsung-exhibit-2-4g/475101-phone-memory-storage.html)
The full description is here. What I have written is basically a copy/paste adapted to the specifics of our phone
http://forum.xda-developers.com/showthread.php?t=1263119
I've done it (few months ago, this comes from the notes I took at that time) but stock ROM is odexed so it's not really useful for me but I can confirm that I had no problem with any apps since I've done this. So either I totally messed up or most of the apps are working fine... This is supposed to give a speed boost for deodexed ROMs (a lot of custom ROMs are deodexed).
I advise caution when you modify build.prop I have no idea what happens if you make a mistake with the file but I would say it's very very bad.
1) Open Terminal Emulator on phone or adb shell from PC and type the following.
adb shell (this is not needed from the terminal)
su
setprop dalvik.vm.verify-bytecode false
setprop dalvik.vm.dexopt-flags v=n,o=v
rm /data/dalvik-cache/*
2) Add these to /system/build.prop
dalvik.vm.verify-bytecode = false
dalvik.vm.dexopt-flags=v=n,o=v
(Copy local.prop or build.prop to SD and edit them. Copy back afterwards. If lines starting with dalvik.vm.verify-bytecode or dalvik.vm.dexopt-flags exist already, please modify them as above. )
For me, the end of the build.prop looks like this
#dalvik.vm.dexopt-flags=m=y
net.bt.name=Android
dalvik.vm.stack-trace-file=/data/anr/traces.txt
dalvik.vm.verify-bytecode = false
dalvik.vm.dexopt-flags=v=n,o=v
Also type following in adb shell or terminal emulator.
adb shell (this is not needed from the terminal)
su
rm /data/dalvik-cache/*
reboot
Reversing the change/undo tweak (I DID NOT TRY, I assume you have to revert the build.prop file first).
adb shell (this is not needed from the terminal)
su
setprop dalvik.vm.verify-bytecode true
rm /data/dalvik-cache/*
reboot
